YAML stands (ironically?) for "YAML ain't markup language" and was intended as a more human readable substitute for programming data structures. The specifications for YAML, unfortunately are not very human readable, so hopefully these rules will suffice.

1. Indentation means scope. Indenting one or more spaces means that the indented stuff belongs to the less indented thing that precedes it. It doesn't matter how many spaces a child element is indented from a parent, but all children must be indented with the same number of spaces. Example: